/* This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/.
 *
 *    Copyright 2019 (c) Fraunhofer IOSB (Author: Klaus Schick)
 *    Copyright 2019 (c) Fraunhofer IOSB (Author: Julius Pfrommer)
 */

#include "ua_server_internal.h"

#if UA_MULTITHREADING >= 100

static void
UA_AsyncOperation_delete(UA_AsyncOperation *ar) {
    UA_CallMethodRequest_clear(&ar->request);
    UA_CallMethodResult_clear(&ar->response);
    UA_free(ar);
}

static UA_StatusCode
UA_AsyncManager_sendAsyncResponse(UA_AsyncManager *am, UA_Server *server,
                                  UA_AsyncResponse *ar) {
    /* Get the session */
    UA_StatusCode res = UA_STATUSCODE_GOOD;
    UA_LOCK(&server->serviceMutex);
    UA_Session* session = UA_Server_getSessionById(server, &ar->sessionId);
    UA_UNLOCK(&server->serviceMutex);
    UA_SecureChannel* channel = NULL;
    UA_ResponseHeader *responseHeader = NULL;
    if(!session) {
        res = UA_STATUSCODE_BADSESSIONIDINVALID;
        UA_LOG_WARNING(&server->config.logger, UA_LOGCATEGORY_SERVER,
                       "UA_Server_InsertMethodResponse: Session is gone");
        goto clean_up;
    }

    /* Check the channel */
    channel = session->header.channel;
    if(!channel) {
        res = UA_STATUSCODE_BADSECURECHANNELCLOSED;
        UA_LOG_WARNING(&server->config.logger, UA_LOGCATEGORY_SERVER,
                       "UA_Server_InsertMethodResponse: Channel is gone");
        goto clean_up;
    }

    /* Okay, here we go, send the UA_CallResponse */
    responseHeader = (UA_ResponseHeader*)
        &ar->response.callResponse.responseHeader;
    responseHeader->requestHandle = ar->requestHandle;
    res = sendResponse(server, session, channel, ar->requestId,
                       (UA_Response*)&ar->response, &UA_TYPES[UA_TYPES_CALLRESPONSE]);
    UA_LOG_DEBUG(&server->config.logger, UA_LOGCATEGORY_SERVER,
                 "UA_Server_SendResponse: Response for Req# %" PRIu32 " sent", ar->requestId);

 clean_up:
    /* Remove from the AsyncManager */
    UA_AsyncManager_removeAsyncResponse(&server->asyncManager, ar);
    return res;
}

/* Integrate operation result in the AsyncResponse and send out the response if
 * it is ready. */
static void
integrateOperationResult(UA_AsyncManager *am, UA_Server *server,
                         UA_AsyncOperation *ao) {
    /* Grab the open request, so we can continue to construct the response */
    UA_AsyncResponse *ar = ao->parent;

    /* Reduce the number of open results */
    ar->opCountdown -= 1;

    UA_LOG_DEBUG(&server->config.logger, UA_LOGCATEGORY_SERVER,
                 "Return result in the server thread with %" PRIu32 " remaining",
                 ar->opCountdown);

    /* Move the UA_CallMethodResult to UA_CallResponse */
    ar->response.callResponse.results[ao->index] = ao->response;
    UA_CallMethodResult_init(&ao->response);

    /* Are we done with all operations? */
    if(ar->opCountdown == 0)
        UA_AsyncManager_sendAsyncResponse(am, server, ar);
}

/* Process all operations in the result queue -> move content over to the
 * AsyncResponse. This is only done by the server thread. */
static void
processAsyncResults(UA_Server *server, void *data) {
    UA_AsyncManager *am = &server->asyncManager;
    while(true) {
        UA_LOCK(&am->queueLock);
        UA_AsyncOperation *ao = TAILQ_FIRST(&am->resultQueue);
        if(ao)
            TAILQ_REMOVE(&am->resultQueue, ao, pointers);
        UA_UNLOCK(&am->queueLock);
        if(!ao)
            break;
        UA_LOG_DEBUG(&server->config.logger, UA_LOGCATEGORY_SERVER,
                     "UA_Server_CallMethodResponse: Got Response: OKAY");
        integrateOperationResult(am, server, ao);
        UA_AsyncOperation_delete(ao);
        am->opsCount--;
    }
}

/* Check if any operations have timed out */
static void
checkTimeouts(UA_Server *server, void *_) {
    /* Timeouts are not configured */
    if(server->config.asyncOperationTimeout <= 0.0)
        return;

    UA_AsyncManager *am = &server->asyncManager;
    const UA_DateTime tNow = UA_DateTime_now();

    UA_LOCK(&am->queueLock);

    /* Loop over the queue of dispatched ops */
    UA_AsyncOperation *op = NULL, *op_tmp = NULL;
    TAILQ_FOREACH_SAFE(op, &am->dispatchedQueue, pointers, op_tmp) {
        /* The timeout has not passed. Also for all elements following in the queue. */
        if(tNow <= op->parent->timeout)
            break;

        /* Mark as timed out and put it into the result queue */
        op->response.statusCode = UA_STATUSCODE_BADTIMEOUT;
        TAILQ_REMOVE(&am->dispatchedQueue, op, pointers);
        TAILQ_INSERT_TAIL(&am->resultQueue, op, pointers);
        UA_LOG_WARNING(&server->config.logger, UA_LOGCATEGORY_SERVER,
                       "Operation was removed due to a timeout");
    }

    /* Loop over the queue of new ops */
    TAILQ_FOREACH_SAFE(op, &am->newQueue, pointers, op_tmp) {
        /* The timeout has not passed. Also for all elements following in the queue. */
        if(tNow <= op->parent->timeout)
            break;

        /* Mark as timed out and put it into the result queue */
        op->response.statusCode = UA_STATUSCODE_BADTIMEOUT;
        TAILQ_REMOVE(&am->newQueue, op, pointers);
        TAILQ_INSERT_TAIL(&am->resultQueue, op, pointers);
        UA_LOG_WARNING(&server->config.logger, UA_LOGCATEGORY_SERVER,
                       "Operation was removed due to a timeout");
    }

    UA_UNLOCK(&am->queueLock);

    /* Integrate async results and send out complete responses */
    processAsyncResults(server, NULL);
}

void
UA_AsyncManager_init(UA_AsyncManager *am, UA_Server *server) {
    memset(am, 0, sizeof(UA_AsyncManager));
    TAILQ_INIT(&am->asyncResponses);
    TAILQ_INIT(&am->newQueue);
    TAILQ_INIT(&am->dispatchedQueue);
    TAILQ_INIT(&am->resultQueue);
    UA_LOCK_INIT(&am->queueLock);

    /* Add a regular callback for cleanup and sending finished responses at a
     * 100s interval. */
    UA_Server_addRepeatedCallback(server, (UA_ServerCallback)checkTimeouts,
                                  NULL, 100.0, &am->checkTimeoutCallbackId);
}

void
UA_AsyncManager_clear(UA_AsyncManager *am, UA_Server *server) {
    removeCallback(server, am->checkTimeoutCallbackId);

    UA_AsyncOperation *ar, *ar_tmp;

    /* Clean up queues */
    UA_LOCK(&am->queueLock);
    TAILQ_FOREACH_SAFE(ar, &am->newQueue, pointers, ar_tmp) {
        TAILQ_REMOVE(&am->newQueue, ar, pointers);
        UA_AsyncOperation_delete(ar);
    }
    TAILQ_FOREACH_SAFE(ar, &am->dispatchedQueue, pointers, ar_tmp) {
        TAILQ_REMOVE(&am->dispatchedQueue, ar, pointers);
        UA_AsyncOperation_delete(ar);
    }
    TAILQ_FOREACH_SAFE(ar, &am->resultQueue, pointers, ar_tmp) {
        TAILQ_REMOVE(&am->resultQueue, ar, pointers);
        UA_AsyncOperation_delete(ar);
    }
    UA_UNLOCK(&am->queueLock);

    /* Remove responses */
    UA_AsyncResponse *current, *temp;
    TAILQ_FOREACH_SAFE(current, &am->asyncResponses, pointers, temp) {
        UA_AsyncManager_removeAsyncResponse(am, current);
    }

    /* Delete all locks */
    UA_LOCK_DESTROY(&am->queueLock);
}

UA_StatusCode
UA_AsyncManager_createAsyncResponse(UA_AsyncManager *am, UA_Server *server,
                                    const UA_NodeId *sessionId,
                                    const UA_UInt32 requestId, const UA_UInt32 requestHandle,
                                    const UA_AsyncOperationType operationType,
                                    UA_AsyncResponse **outAr) {
    UA_AsyncResponse *newentry = (UA_AsyncResponse*)UA_calloc(1, sizeof(UA_AsyncResponse));
    if(!newentry)
        return UA_STATUSCODE_BADOUTOFMEMORY;

    UA_StatusCode res = UA_NodeId_copy(sessionId, &newentry->sessionId);
    if(res != UA_STATUSCODE_GOOD) {
        UA_free(newentry);
        return res;
    }

    am->asyncResponsesCount += 1;
    newentry->requestId = requestId;
    newentry->requestHandle = requestHandle;
    newentry->timeout = UA_DateTime_now();
    if(server->config.asyncOperationTimeout > 0.0)
        newentry->timeout += (UA_DateTime)
            (server->config.asyncOperationTimeout * (UA_DateTime)UA_DATETIME_MSEC);
    TAILQ_INSERT_TAIL(&am->asyncResponses, newentry, pointers);

    *outAr = newentry;
    return UA_STATUSCODE_GOOD;
}

/* Remove entry and free all allocated data */
void
UA_AsyncManager_removeAsyncResponse(UA_AsyncManager *am, UA_AsyncResponse *ar) {
    TAILQ_REMOVE(&am->asyncResponses, ar, pointers);
    am->asyncResponsesCount -= 1;
    UA_CallResponse_clear(&ar->response.callResponse);
    UA_NodeId_clear(&ar->sessionId);
    UA_free(ar);
}

/* Enqueue next MethodRequest */
UA_StatusCode
UA_AsyncManager_createAsyncOp(UA_AsyncManager *am, UA_Server *server,
                              UA_AsyncResponse *ar, size_t opIndex,
                              const UA_CallMethodRequest *opRequest) {
    if(server->config.maxAsyncOperationQueueSize != 0 &&
       am->opsCount >= server->config.maxAsyncOperationQueueSize) {
        UA_LOG_WARNING(&server->config.logger, UA_LOGCATEGORY_SERVER,
                       "UA_Server_SetNextAsyncMethod: Queue exceeds limit (%d).",
                       (int unsigned)server->config.maxAsyncOperationQueueSize);
        return UA_STATUSCODE_BADUNEXPECTEDERROR;
    }

    UA_AsyncOperation *ao = (UA_AsyncOperation*)UA_calloc(1, sizeof(UA_AsyncOperation));
    if(!ao) {
        UA_LOG_ERROR(&server->config.logger, UA_LOGCATEGORY_SERVER,
                     "UA_Server_SetNextAsyncMethod: Mem alloc failed.");
        return UA_STATUSCODE_BADOUTOFMEMORY;
    }

    UA_StatusCode result = UA_CallMethodRequest_copy(opRequest, &ao->request);
    if(result != UA_STATUSCODE_GOOD) {
        UA_LOG_ERROR(&server->config.logger, UA_LOGCATEGORY_SERVER,
                     "UA_Server_SetAsyncMethodResult: UA_CallMethodRequest_copy failed.");                
        UA_free(ao);
        return result;
    }

    UA_CallMethodResult_init(&ao->response);
    ao->index = opIndex;
    ao->parent = ar;

    UA_LOCK(&am->queueLock);
    TAILQ_INSERT_TAIL(&am->newQueue, ao, pointers);
    am->opsCount++;
    ar->opCountdown++;
    UA_UNLOCK(&am->queueLock);

    if(server->config.asyncOperationNotifyCallback)
        server->config.asyncOperationNotifyCallback(server);

    return UA_STATUSCODE_GOOD;
}

/* Get and remove next Method Call Request */
UA_Boolean
UA_Server_getAsyncOperationNonBlocking(UA_Server *server, UA_AsyncOperationType *type,
                                       const UA_AsyncOperationRequest **request,
                                       void **context, UA_DateTime *timeout) {
    UA_AsyncManager *am = &server->asyncManager;

    UA_Boolean bRV = false;
    *type = UA_ASYNCOPERATIONTYPE_INVALID;
    UA_LOCK(&am->queueLock);
    UA_AsyncOperation *ao = TAILQ_FIRST(&am->newQueue);
    if(ao) {
        TAILQ_REMOVE(&am->newQueue, ao, pointers);
        TAILQ_INSERT_TAIL(&am->dispatchedQueue, ao, pointers);
        *type = UA_ASYNCOPERATIONTYPE_CALL;
        *request = (UA_AsyncOperationRequest*)&ao->request;
        *context = (void*)ao;
        if(timeout)
            *timeout = ao->parent->timeout;
        bRV = true;
    }
    UA_UNLOCK(&am->queueLock);

    return bRV;
}

/* Worker submits Method Call Response */
void
UA_Server_setAsyncOperationResult(UA_Server *server,
                                  const UA_AsyncOperationResponse *response,
                                  void *context) {
    UA_AsyncManager *am = &server->asyncManager;

    UA_AsyncOperation *ao = (UA_AsyncOperation*)context;
    if(!ao) {
        /* Something went wrong. Not a good AsyncOp. */
        UA_LOG_WARNING(&server->config.logger, UA_LOGCATEGORY_SERVER,
                       "UA_Server_SetAsyncMethodResult: Invalid context");
        return;
    }

    UA_LOCK(&am->queueLock);

    /* See if the operation is still in the dispatched queue. Otherwise it has
     * been removed due to a timeout.
     *
     * TODO: Add a tree-structure for the dispatch queue. The linear lookup does
     * not scale. */
    UA_Boolean found = false;
    UA_AsyncOperation *op = NULL;
    TAILQ_FOREACH(op, &am->dispatchedQueue, pointers) {
        if(op == ao) {
            found = true;
            break;
        }
    }

    if(!found) {
        UA_LOG_WARNING(&server->config.logger, UA_LOGCATEGORY_SERVER,
                       "UA_Server_SetAsyncMethodResult: The operation has timed out");
        UA_UNLOCK(&am->queueLock);
        return;
    }

    /* Copy the result into the internal AsyncOperation */
    UA_StatusCode result =
        UA_CallMethodResult_copy(&response->callMethodResult, &ao->response);
    if(result != UA_STATUSCODE_GOOD) {
        UA_LOG_WARNING(&server->config.logger, UA_LOGCATEGORY_SERVER,
                       "UA_Server_SetAsyncMethodResult: UA_CallMethodResult_copy failed.");
        ao->response.statusCode = UA_STATUSCODE_BADOUTOFMEMORY;
    }

    /* Move to the result queue */
    TAILQ_REMOVE(&am->dispatchedQueue, ao, pointers);
    TAILQ_INSERT_TAIL(&am->resultQueue, ao, pointers);

    UA_UNLOCK(&am->queueLock);

    UA_LOG_DEBUG(&server->config.logger, UA_LOGCATEGORY_SERVER,
                 "Set the result from the worker thread");
}

/******************/
/* Server Methods */
/******************/

static UA_StatusCode
setMethodNodeAsync(UA_Server *server, UA_Session *session,
                   UA_Node *node, UA_Boolean *isAsync) {
    if(node->head.nodeClass != UA_NODECLASS_METHOD)
        return UA_STATUSCODE_BADNODECLASSINVALID;
    node->methodNode.async = *isAsync;
    return UA_STATUSCODE_GOOD;
}

UA_StatusCode
UA_Server_setMethodNodeAsync(UA_Server *server, const UA_NodeId id,
                             UA_Boolean isAsync) {
    return UA_Server_editNode(server, &server->adminSession, &id,
                              (UA_EditNodeCallback)setMethodNodeAsync, &isAsync);
}

UA_StatusCode
UA_Server_processServiceOperationsAsync(UA_Server *server, UA_Session *session,
                                        UA_UInt32 requestId, UA_UInt32 requestHandle,
                                        UA_AsyncServiceOperation operationCallback,
                                        const size_t *requestOperations,
                                        const UA_DataType *requestOperationsType,
                                        size_t *responseOperations,
                                        const UA_DataType *responseOperationsType,
                                        UA_AsyncResponse **ar) {
    size_t ops = *requestOperations;
    if(ops == 0)
        return UA_STATUSCODE_BADNOTHINGTODO;

    /* Allocate the response array. No padding after size_t */
    void **respPos = (void**)((uintptr_t)responseOperations + sizeof(size_t));
    *respPos = UA_Array_new(ops, responseOperationsType);
    if(!*respPos)
        return UA_STATUSCODE_BADOUTOFMEMORY;
    *responseOperations = ops;

    /* Finish / dispatch the operations. This may allocate a new AsyncResponse internally */
    uintptr_t respOp = (uintptr_t)*respPos;
    uintptr_t reqOp = *(uintptr_t*)((uintptr_t)requestOperations + sizeof(size_t));
    for(size_t i = 0; i < ops; i++) {
        operationCallback(server, session, requestId, requestHandle,
                          i, (void*)reqOp, (void*)respOp, ar);
        reqOp += requestOperationsType->memSize;
        respOp += responseOperationsType->memSize;
    }

    return UA_STATUSCODE_GOOD;
}

#endif